[PATCH v3 5/9] module: Make module loading policy usable without MODULE_SIG

[Thomas Weißschuh]

The loading policy functionality will also be used by the hash-based
module validation. Split it out from CONFIG_MODULE_SIG so it is usable
by both.

Signed-off-by: Thomas Weißschuh <li...@weissschuh.net>
---
 include/linux/module.h  |  8 ++++----
 kernel/module/Kconfig   |  6 +++++-
 kernel/module/main.c    | 26 +++++++++++++++++++++++++-
 kernel/module/signing.c | 21 ---------------------
 4 files changed, 34 insertions(+), 27 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 
d94b196d5a34e104d81308df4b150452eb96cdc9..68aa8bbd33acc84e013dc575ee88bd4e3101f9f4
 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -453,7 +453,7 @@ struct module {
        const u32 *gpl_crcs;
        bool using_gplonly_symbols;
 
-#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_POLICY
        /* Signature was verified. */
        bool sig_ok;
 #endif
@@ -921,14 +921,14 @@ static inline bool retpoline_module_ok(bool has_retpoline)
 }
 #endif
 
-#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_POLICY
 bool is_module_sig_enforced(void);
 
 static inline bool module_sig_ok(struct module *module)
 {
        return module->sig_ok;
 }
-#else  /* !CONFIG_MODULE_SIG */
+#else  /* !CONFIG_MODULE_SIG_POLICY */
 static inline bool is_module_sig_enforced(void)
 {
        return false;
@@ -938,7 +938,7 @@ static inline bool module_sig_ok(struct module *module)
 {
        return true;
 }
-#endif /* CONFIG_MODULE_SIG */
+#endif /* CONFIG_MODULE_SIG_POLICY */
 
 #if defined(CONFIG_MODULES) && defined(CONFIG_KALLSYMS)
 int module_kallsyms_on_each_symbol(const char *modname,
diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
index 
c51f25538d0ea66e6486ad0be6684173cd0140b5..a3146e9378fcd3292a756a2a7ea5241524cbc408
 100644
--- a/kernel/module/Kconfig
+++ b/kernel/module/Kconfig
@@ -265,9 +265,13 @@ config MODULE_SIG
          debuginfo strip done by some packagers (such as rpmbuild) and
          inclusion into an initramfs that wants the module size reduced.
 
+config MODULE_SIG_POLICY
+       def_bool y
+       depends on MODULE_SIG
+
 config MODULE_SIG_FORCE
        bool "Require modules to be validly signed"
-       depends on MODULE_SIG
+       depends on MODULE_SIG_POLICY
        help
          Reject unsigned modules or signed modules for which we don't have a
          key.  Without this, such modules will simply taint the kernel.
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 
a2859dc3eea66ec19991e7e4afb5bbcae2c2d167..83c66205556fdde92152c131f1f58229c4f7f734
 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2432,7 +2432,7 @@ static void module_augment_kernel_taints(struct module 
*mod, struct load_info *i
                                mod->name);
                add_taint_module(mod, TAINT_TEST, LOCKDEP_STILL_OK);
        }
-#ifdef CONFIG_MODULE_SIG
+#ifdef CONFIG_MODULE_SIG_POLICY
        mod->sig_ok = info->sig_ok;
        if (!mod->sig_ok) {
                pr_notice_once("%s: module verification failed: signature "
@@ -3808,3 +3808,27 @@ static int module_debugfs_init(void)
 }
 module_init(module_debugfs_init);
 #endif
+
+#ifdef CONFIG_MODULE_SIG_POLICY
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "module."
+
+static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
+module_param(sig_enforce, bool_enable_only, 0644);
+
+/*
+ * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
+ * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
+ */
+bool is_module_sig_enforced(void)
+{
+       return sig_enforce;
+}
+EXPORT_SYMBOL(is_module_sig_enforced);
+
+void set_module_sig_enforced(void)
+{
+       sig_enforce = true;
+}
+#endif
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index 
a2ff4242e623d5d4e87d2f3d139d8620fb937579..e51920605da14771601327ea596dad2e12400518
 100644
--- a/kernel/module/signing.c
+++ b/kernel/module/signing.c
@@ -16,27 +16,6 @@
 #include <uapi/linux/module.h>
 #include "internal.h"
 
-#undef MODULE_PARAM_PREFIX
-#define MODULE_PARAM_PREFIX "module."
-
-static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
-module_param(sig_enforce, bool_enable_only, 0644);
-
-/*
- * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
- * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
- */
-bool is_module_sig_enforced(void)
-{
-       return sig_enforce;
-}
-EXPORT_SYMBOL(is_module_sig_enforced);
-
-void set_module_sig_enforced(void)
-{
-       sig_enforce = true;
-}
-
 /*
  * Verify the signature on a module.
  */

-- 
2.49.0